I had a similar issue with my artwork where I was accused of stealing my own stuff not so long ago. I go off another name elsewhere. After which I proved I was the other artist and admins on that site apologized for the inconvenience. Have you contacted artist on deviant art to see if they have a Hentai foundry account under another name? It could save a lot of issues for the artist as it is stressful having an account wrongly suspended as you can imagine. Provide a link back to it, and if they say no, it's not them, then at least the artist then can take action.

Nevermind, checked it out, he's not the artists but he also doesn't claim the art is his but a friends. So we'll see what admins do. He doesn't have art up so possibly been removed by user or admins already.